U.S. Pat. No. 3,800,677 granted Apr. 2, 1974 to Charles W. Jones and Dwight L. Stetler discloses apparatus for forming, and U.S. Pat. No. 3,775,943 granted Dec. 4, 1973 to Charles W. Jones discloses apparatus for filling with liquid and sealing, a carton of the type that the apparatus to be described hereinafter is intended to seal after having been filled. The carton itself is generally of the type shown in U.S. Pat. No. 3,749,300 granted July 31, 1973 to Charles W. Jones. It is a carton of rectangular cross section, preferably formed from a T-shaped blank of polyethylene coated paperboard. The T-shaped blank provides four side wall panels. An end one of the side walls has integral therewith two end covers or caps which, after the blank has been formed into a tube of rectangular cross section, are folded down upon and sealed to the open ends of the tube. As shown in U.S. Pat. No. 3,800,677 the carton blank is provided on one of its sides with an access flap to which is attached on the inside of the carton a straw or sipper, and the liquid contents of the carton may be consumed by lifting the access flap thereby exposing an end of the sipper from which the contents of the carton may be drawn into the mouth. In the formation of the carton by the apparatus shown in U.S. Pat. No. 3,800,677 both ends of the carton are closed and sealed prior to the filling of the carton, and in accordance with the disclosure of U.S. Pat. No. 3,775,943 the access flap is lifted and the cartons are filled through the access aperture, after which the aperture is sealed by the application of a length of tape covering the access flap which has been pressed back down into the access aperture.
It is a more conventional practice to fill containers for liquids, whether of paperboard, metal or glass, from the top, and container filling machines of this type are known in the art. Heretofore cartons for marketing beverage types of liquids have been for the most part one or the other of two types. One of these, which has a generally flat bottom and top, which enables them to be stacked, consists of four separate component parts. These parts are an open ended tubular body, two end closure members which are crimped upon and adhesively interengaged with the ends of the tubular body and a closure cap that is liftably attached to one of the end members and that squeezes down into and closes an access orifice in that member. The production of such a carton is rendered complex by the necessity for handling and sealing together the several component parts.
The other type of carton is derived from a one-piece blank of sheet stock comprised of four side wall panels that may be folded around to form an open ended tube. Each side wall panel has at each end a closure flap component, each such component being generally rectangular and having an area at least equal to and in some instances exceeding one-half the area of the cross section of the tubular portion. Those that form the bottom of the carton fold in on one another with considerable superposition of flaps so that the bottom of the carton is comprised of several thicknesses of paperboard but is flat. At the top of the carton two opposite ones of the top closure flaps have scorings which delineate a multiplicity of triangles. After the filling of the carton two of the flaps are folded in and bent upon the scoring lines delineating the triangles and the other two are brought together not in flat overlapping relation but in an upward slope of both sides with marginal portions at their edges brought together upstanding and in abutting relation. These may be sealed together by melting the polyethylene coatings and without the use of a mandrel, but the heat for melting the polyethylene must penetrate superimposed layers of paper stock in order to reach the innermost polyethylene coatings and considerably more heat must be applied than is required when it can be applied directly to the surfaces to be sealed together. Also, the upper end of the carton slopes from the center toward two sides of the carton resembling a roof with a central ridge, and the filled cartons are not adapted to being stacked for packing and shipping.